The runway at Stansted Airport was closed while police dealt with a "security alert" on a plane.
Scores of flights were left circling the skies following the incident this evening, reported to have been sparked by a bomb threat.
Essex Police said the aircraft involved has been "moved to a secure part of the airport" as enquiries continue.
The flight affected was easyJet U27920 to Amsterdam.
The aircraft was an A319.
The force said at just before 9.15pm: "We are currently dealing with a security alert on a plane at #Stansted Airport.
Did you witness this incident? Let us know at webnews@mirror.co.uk
"The plane has been moved to a secure part of the airport while we carry out enquiries.
"The runway was closed for a short time but the airport is now fully open. We’ll update when we can."
A London Stansted Airport spokesperson said: “A flight due to depart from London Stansted to Amsterdam is currently parked on a remote stand while police conduct extra security checks.
"The airport’s runway was closed for a short time but has now fully re-opened.”
A passenger whose plane was diverted said on Twitter: "Been diverted to Birmingham after circling Stansted for half hour.
"Should be flying back after re-fueling now it's open. Thankfully everything is ok at Stansted now."
According to Air Live arrivals were not available between 6.20pm and 8.50pm.
It described the incident as a "bomb threat", though this has not been confirmed by the police or airport.
